/*
 * Copyright 2005,2009 Ivan SZKIBA
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.ini4j;

import org.ini4j.spi.IniFormatter;
import org.ini4j.spi.IniHandler;
import org.ini4j.spi.IniParser;
import org.ini4j.spi.RegBuilder;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.InterruptedIOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;

import java.net.URL;

public class Reg extends BasicRegistry implements Registry, Persistable,
		Configurable {
	private static final long serialVersionUID = -1485602876922985912L;
	protected static final String DEFAULT_SUFFIX = ".reg";
	protected static final String TMP_PREFIX = "reg-";
	private static final int STDERR_BUFF_SIZE = 8192;
	private static final String PROP_OS_NAME = "os.name";
	private static final boolean WINDOWS = Config.getSystemProperty(
			PROP_OS_NAME, "Unknown").startsWith("Windows");
	private static final char CR = '\r';
	private static final char LF = '\n';
	private Config _config;
	private File _file;

	public Reg() {
		Config cfg = Config.getGlobal().clone();

		cfg.setEscape(false);
		cfg.setGlobalSection(false);
		cfg.setEmptyOption(true);
		cfg.setMultiOption(true);
		cfg.setStrictOperator(true);
		cfg.setEmptySection(true);
		cfg.setPathSeparator(KEY_SEPARATOR);
		cfg.setFileEncoding(FILE_ENCODING);
		cfg.setLineSeparator(LINE_SEPARATOR);
		_config = cfg;
	}

	public Reg(String registryKey) throws IOException {
		this();
		read(registryKey);
	}

	public Reg(File input) throws IOException, InvalidFileFormatException {
		this();
		_file = input;
		load();
	}

	public Reg(URL input) throws IOException, InvalidFileFormatException {
		this();
		load(input);
	}

	public Reg(InputStream input) throws IOException,
			InvalidFileFormatException {
		this();
		load(input);
	}

	public Reg(Reader input) throws IOException, InvalidFileFormatException {
		this();
		load(input);
	}

	public static boolean isWindows() {
		return WINDOWS;
	}

	@Override
	public Config getConfig() {
		return _config;
	}

	public void setConfig(Config value) {
		_config = value;
	}

	@Override
	public File getFile() {
		return _file;
	}

	@Override
	public void setFile(File value) {
		_file = value;
	}

	@Override
	public void load() throws IOException, InvalidFileFormatException {
		if (_file == null) {
			throw new FileNotFoundException();
		}

		load(_file);
	}

	@Override
	public void load(InputStream input) throws IOException,
			InvalidFileFormatException {
		load(new InputStreamReader(input, getConfig().getFileEncoding()));
	}

	@Override
	public void load(URL input) throws IOException, InvalidFileFormatException {
		load(new InputStreamReader(input.openStream(), getConfig()
				.getFileEncoding()));
	}

	@Override
	public void load(Reader input) throws IOException,
			InvalidFileFormatException {
		int newline = 2;
		StringBuilder buff = new StringBuilder();

		for (int c = input.read(); c != -1; c = input.read()) {
			if (c == LF) {
				newline--;
				if (newline == 0) {
					break;
				}
			} else if ((c != CR) && (newline != 1)) {
				buff.append((char) c);
			}
		}

		if (buff.length() == 0) {
			throw new InvalidFileFormatException("Missing version header");
		}

		if (!buff.toString().equals(getVersion())) {
			throw new InvalidFileFormatException("Unsupported version: "
					+ buff.toString());
		}

		IniParser.newInstance(getConfig()).parse(input, newBuilder());
	}

	@Override
	public void load(File input) throws IOException, InvalidFileFormatException {
		load(input.toURI().toURL());
	}

	public void read(String registryKey) throws IOException {
		File tmp = createTempFile();

		try {
			regExport(registryKey, tmp);
			load(tmp);
		} finally {
			tmp.delete();
		}
	}

	@Override
	public void store() throws IOException {
		if (_file == null) {
			throw new FileNotFoundException();
		}

		store(_file);
	}

	@Override
	public void store(OutputStream output) throws IOException {
		store(new OutputStreamWriter(output, getConfig().getFileEncoding()));
	}

	@Override
	public void store(Writer output) throws IOException {
		output.write(getVersion());
		output.write(getConfig().getLineSeparator());
		output.write(getConfig().getLineSeparator());
		store(IniFormatter.newInstance(output, getConfig()));
	}

	@Override
	public void store(File output) throws IOException {
		OutputStream stream = new FileOutputStream(output);

		store(stream);
		stream.close();
	}

	public void write() throws IOException {
		File tmp = createTempFile();

		try {
			store(tmp);
			regImport(tmp);
		} finally {
			tmp.delete();
		}
	}

	protected IniHandler newBuilder() {
		return RegBuilder.newInstance(this);
	}

	@Override
	boolean isTreeMode() {
		return getConfig().isTree();
	}

	@Override
	char getPathSeparator() {
		return getConfig().getPathSeparator();
	}

	@Override
	boolean isPropertyFirstUpper() {
		return getConfig().isPropertyFirstUpper();
	}

	void exec(String[] args) throws IOException {
		Process proc = Runtime.getRuntime().exec(args);

		try {
			int status = proc.waitFor();

			if (status != 0) {
				Reader in = new InputStreamReader(proc.getErrorStream());
				char[] buff = new char[STDERR_BUFF_SIZE];
				int n = in.read(buff);

				in.close();
				throw new IOException(new String(buff, 0, n).trim());
			}
		} catch (InterruptedException x) {
			throw (IOException) (new InterruptedIOException().initCause(x));
		}
	}

	private File createTempFile() throws IOException {
		File ret = File.createTempFile(TMP_PREFIX, DEFAULT_SUFFIX);

		ret.deleteOnExit();

		return ret;
	}

	private void regExport(String registryKey, File file) throws IOException {
		requireWindows();
		exec(new String[] { "cmd", "/c", "reg", "export", registryKey,
				file.getAbsolutePath() });
	}

	private void regImport(File file) throws IOException {
		requireWindows();
		exec(new String[] { "cmd", "/c", "reg", "import",
				file.getAbsolutePath() });
	}

	private void requireWindows() {
		if (!WINDOWS) {
			throw new UnsupportedOperationException(
					"Unsupported operating system or runtime environment");
		}
	}
}
